Brian:

Thanks very much for your help.  Your example is clear and I expect it to save me lots
of time and headaches when I write my code.  Thanks also for your narrative explanation.
 You have gone above and beyond the call.

Thanks again.

Kevin
  ----- Original Message ----- 
  From: Brian McGinnis 
  To: ecs-list@netbloc.com 
  Sent: Thursday, October 26, 2000 12:16 PM
  Subject: Re: [ECS] Creating ECS interface to my Access Control System


  <I have sent this msg in HTML format to hopefully preserve the formatting.  I apologize
in advance if this causes problems for anyone.>

  Hi Kevin,
  I decided to post this directly to the list in case anyone else cares.  This is one

  example about using the Serial-Byte item type to poll devices not directly supported
by 
  ECS.

  First of all, everything is received a byte (character) at a time.  At first this
may 
  seem like it would make the event writing more difficult, but I think you'll find

  that's not really the case.  At any rate, most any programming language that you would

  use would be set up the same way.  Note: You can use the SEND->COM{d} state on a text

  item to send an entire string of characters out a COM port.  This can be useful for

  delivering lengthy commands to the device.

  This sample sends a one-byte command to a serial device known as a "Hot Little 
  Therm" that has temp sensors attached to it.  The device responds with a list of temp

  sensor Ids and the temperature.  For example, if I have two temp sensors attached
to 
  the first HLT device, then:

  I send: "16"  (no quotes) by setting  HLT:Hot Little Therm to 16

  Device responds:

  V93-7200<CR><LF>                   ;Firmware revision and serial number
  S1<CR><LF>                         ;Digital Input level
  T10460247000000d9 +019.8<CR><LF>   ;Probe #1 ID and temp
  T10fdd94600000087 -005.5<CR><LF>   ;Probe #2 ID and temp
  Z<CR><LF>                          ;End of list

  16 is the command that tells the HLT to send back all the Ids and their readings 
  attached to the first HLT device.

  ECS's job then, will be to parse this returned data for the probe id so that it can
be 
  matched with an actual ECS item, along with it's temp value.

  Let's take a look at the items involved:

  ;This is the actual device defined as a Serial-Byte item
  Item:HLT:Hot Little Therm Type:Serial-Byte  Acc:User/Owner
   Initial State:(none)     Backup:No
   Serial Port  :COM1
   Baud Rate    :1200
   Parity       :None
   Stop Bits    :1

  ;This text item will hold the returned temp value for probe 1
  Item:HLT:Probe 1  Type:Text   Acc:User/Owner
   Initial State:(none)     Backup:No
   Text         :

  ;This text item will hold the returned temp value for probe 2
  Item:HLT:Probe 2  Type:Text   Acc:User/Owner
   Initial State:(none)     Backup:No
   Text         :

  ;The text item holds the ID of probe 1.  Each temp sensor has a
  ;unique ID.  We take advantage of this fact to make sure we're
  ;matching the right temp value with the right probe
  Item:HLT:Probe 1 ID  Type:Text   Acc:User/Maint
   Initial State:(none)     Backup:No
   Text         :T10460247000000d9

  ;As above, but the ID of probe 2
  Item:HLT:Probe 2 ID  Type:Text   Acc:User/Maint
   Initial State:(none)     Backup:No
   Text         :T10fdd94600000087

  ;This character item holds the byte just read from the Serial-Byte
  ;device
  Item:HLT:Byte Read  Type:Character   Acc:User/Maint
   Initial State:(none)     Backup:No

  ;This text item holds the probe id that is currently being read.
  ;It is built one character at a time.
  Item:HLT:Probe ID Text  Type:Text   Acc:User/Maint
   Initial State:(none)     Backup:No
   Text         :

  ;This number item keeps track of what type of data is coming in from
  ;the device: 1 means it is receiving a probe ID, 2 means that it is
  ;receiving a temperature, and 3 means we have completed reading 
  ;one probe id and temperature.
  Item:HLT:Read Mode  Type:Number   Acc:User/Maint
   Initial State:(none)     Backup:No

  ;This text item holds the temperature currently coming in from
  ;the device.  It is built one character at a time.
  Item:HLT:Probe Temp Text Type:Text   Acc:User/Maint
   Initial State:(none)     Backup:No
   Text         :


  OK, here is the event that actually reads the probe Ids and temps coming in from the
device:

  Event: Read HLT   Called ?:No
   ;
   ; Read Hot Little Therm Device
   ;
   ;Fetch character, if any, from the device.
   Do HLT:Byte Read  Set  HLT:Hot Little Therm
   ;Check it for a value. Do not test the Serial-Byte item directly,
   ;load it into another item as we've done here first, then
   ;test that.
   ;If there is no activity on the port, then exit the event.
   If HLT:Byte Read  Is  None
   Then Event-Exit  Set  True
   ;
   ;If there is activity, then start a loop to process all characters
   ;sitting in the buffer. By setting up this looping structure, we
   ;can read more than one character from the device per event pass.
   WHILE HLT:Byte Read  Is Not  None
   ;
   ; If text coming in begins with a T, we know it is going to
   ; be the Probe ID, so clear the text item in preparation and
   ; set the mode to indicate probe ID data is coming.
   If HLT:Byte Read          Is  T
   Then HLT:Probe ID Text    Set  Reset
   Then HLT:Read Mode        Set  1
   ;
   ; On the other hand, if we find a space in the text,
  ; it always precedes a temp value, so clear the text
  ; item in preparation and set the mode to indicate
  ; temperature data in coming.
   If HLT:Byte Read             Is  <Space>
   Then HLT:Probe Temp Text     Set  Reset
   Then HLT:Read Mode           Set  2
   ;
   ; If we find a <CR> and the mode is 2 (temp value),
  ; then we know we're done reading this probe's data.
  ; It's time to evaluate what we've got.
   If HLT:Byte Read      Is  <CR>
   And HLT:Read Mode     Is  2
   Then HLT:Read Mode    Set  3
   ;
   ; Build up the 2 strings according to what mode we're in
   ; character by character.
   If HLT:Read Mode       Is  1
   Then HLT:Probe ID Text T1/A<-Stt HLT:Byte Read
   ;
   If HLT:Read Mode   Is  2
   And HLT:Byte Read   Is Not <Space>
   Then HLT:Probe Temp Text T1/A<-Stt HLT:Byte Read
   ;
   ; Assign temperature value to correct probe.
   BEGINIF HLT:Read Mode  Is Now  3
   If HLT:Probe ID Text   Is/T1   HLT:Probe 1 ID
   Then HLT:Probe 1       T1<-T1  HLT:Probe Temp Text
   If HLT:Probe ID Text   Is/T1   HLT:Probe 2 ID
   Then HLT:Probe 2       T1<-T1  HLT:Probe Temp Text
   ENDIF
   ;
   ; Check for another byte in the buffer now, without waiting
   ; for another event pass.  This speeds up reading from the
   ; device dramatically.
   Do HLT:Byte Read  Set  HLT:Hot Little Therm
   ; Loop back to the beginning and test the HLT:Byte Read item
   ; for data.
   ENDWHILE
   End


  So, sending the command to the device is easy, whenever you feel the need for updated

  temp info, just:

  DO HLT:Hot Little Therm SET 16

  The event will take care of the rest.

  Some additional things to think about:

  The serial data may not arrive at the port in one big chunk.  Don't write an event
that sets up a loop once data is received at the port and considers all of the data
to be present in that loop.  A looping structure is great for processing all of the
data sitting at the port, but don't count on all of it being there at once.  The above
event is written to handle this.  It reads data in a looping structure as long as it's
there, but doesn't make any decisions about what to do with it until it sees the appropriate
terminations.  This could take one event pass, 
  or many.

  I hope this helps get you started.
  Brian

----- Original Message -----

From: Brian McGinnis

To: ecs-list@netbloc.com

Sent: Thursday, October 26, 2000 12:16 PM

Subject: Re: [ECS] Creating ECS interface to my Access Control System

<I have sent this msg in HTML format to hopefully preserve the formatting.  I apologize in advance if this causes problems for anyone.>

 

Hi Kevin,
I decided to post this directly to the list in case anyone else cares.  This is one
example about using the Serial-Byte item type to poll devices not directly supported by
ECS.

 

First of all, everything is received a byte (character) at a time.  At first this may
seem like it would make the event writing more difficult, but I think you'll find
that's not really the case.  At any rate, most any programming language that you would
use would be set up the same way.  Note: You can use the SEND->COM{d} state on a text
item to send an entire string of characters out a COM port.  This can be useful for
delivering lengthy commands to the device.

 

This sample sends a one-byte command to a serial device known as a "Hot Little
Therm" that has temp sensors attached to it.  The device responds with a list of temp
sensor Ids and the temperature.  For example, if I have two temp sensors attached to
the first HLT device, then:

 

I send: "16"  (no quotes) by setting  HLT:Hot Little Therm to 16

 

Device responds:

 

V93-7200<CR><LF>                   ;Firmware revision and serial number
S1<CR><LF>                         ;Digital Input level
T10460247000000d9 +019.8<CR><LF>   ;Probe #1 ID and temp
T10fdd94600000087 -005.5<CR><LF>   ;Probe #2 ID and temp
Z<CR><LF>                          ;End of list

 

16 is the command that tells the HLT to send back all the Ids and their readings
attached to the first HLT device.

 

ECS's job then, will be to parse this returned data for the probe id so that it can be
matched with an actual ECS item, along with it's temp value.

 

Let's take a look at the items involved:

 

;This is the actual device defined as a Serial-Byte item
Item:HLT:Hot Little Therm Type:Serial-Byte  Acc:User/Owner
 Initial State:(none)     Backup:No
 Serial Port  :COM1
 Baud Rate    :1200
 Parity       :None
 Stop Bits    :1

 

;This text item will hold the returned temp value for probe 1
Item:HLT:Probe 1  Type:Text   Acc:User/Owner
 Initial State:(none)     Backup:No
 Text         :

 

;This text item will hold the returned temp value for probe 2
Item:HLT:Probe 2  Type:Text   Acc:User/Owner
 Initial State:(none)     Backup:No
 Text         :

 

;The text item holds the ID of probe 1.  Each temp sensor has a
;unique ID.  We take advantage of this fact to make sure we're
;matching the right temp value with the right probe
Item:HLT:Probe 1 ID  Type:Text   Acc:User/Maint
 Initial State:(none)     Backup:No
 Text         :T10460247000000d9

 

;As above, but the ID of probe 2
Item:HLT:Probe 2 ID  Type:Text   Acc:User/Maint
 Initial State:(none)     Backup:No
 Text         :T10fdd94600000087

 

;This character item holds the byte just read from the Serial-Byte
;device
Item:HLT:Byte Read  Type:Character   Acc:User/Maint
 Initial State:(none)     Backup:No

 

;This text item holds the probe id that is currently being read.
;It is built one character at a time.
Item:HLT:Probe ID Text  Type:Text   Acc:User/Maint
 Initial State:(none)     Backup:No
 Text         :

 

;This number item keeps track of what type of data is coming in from
;the device: 1 means it is receiving a probe ID, 2 means that it is
;receiving a temperature, and 3 means we have completed reading
;one probe id and temperature.
Item:HLT:Read Mode  Type:Number   Acc:User/Maint
 Initial State:(none)     Backup:No

 

;This text item holds the temperature currently coming in from
;the device.  It is built one character at a time.
Item:HLT:Probe Temp Text Type:Text   Acc:User/Maint
 Initial State:(none)     Backup:No
 Text         :

 

OK, here is the event that actually reads the probe Ids and temps coming in from the device:

 

Event: Read HLT   Called ?:No
 ;
 ; Read Hot Little Therm Device
 ;
 ;Fetch character, if any, from the device.
 Do HLT:Byte Read  Set  HLT:Hot Little Therm
 ;Check it for a value. Do not test the Serial-Byte item directly,
 ;load it into another item as we've done here first, then
 ;test that.
 ;If there is no activity on the port, then exit the event.
 If HLT:Byte Read  Is  None
 Then Event-Exit  Set  True
 ;
 ;If there is activity, then start a loop to process all characters
 ;sitting in the buffer. By setting up this looping structure, we
 ;can read more than one character from the device per event pass.
 WHILE HLT:Byte Read  Is Not  None
 ;
 ; If text coming in begins with a T, we know it is going to
 ; be the Probe ID, so clear the text item in preparation and
 ; set the mode to indicate probe ID data is coming.
 If HLT:Byte Read          Is  T
 Then HLT:Probe ID Text    Set  Reset
 Then HLT:Read Mode        Set  1
 ;
 ; On the other hand, if we find a space in the text,
; it always precedes a temp value, so clear the text
; item in preparation and set the mode to indicate
; temperature data in coming.
 If HLT:Byte Read             Is  <Space>
 Then HLT:Probe Temp Text     Set  Reset
 Then HLT:Read Mode           Set  2
 ;
 ; If we find a <CR> and the mode is 2 (temp value),
; then we know we're done reading this probe's data.
; It's time to evaluate what we've got.
 If HLT:Byte Read      Is  <CR>
 And HLT:Read Mode     Is  2
 Then HLT:Read Mode    Set  3
 ;
 ; Build up the 2 strings according to what mode we're in
 ; character by character.
 If HLT:Read Mode       Is  1
 Then HLT:Probe ID Text T1/A<-Stt HLT:Byte Read
 ;
 If HLT:Read Mode   Is  2
 And HLT:Byte Read   Is Not <Space>
 Then HLT:Probe Temp Text T1/A<-Stt HLT:Byte Read
 ;
 ; Assign temperature value to correct probe.
 BEGINIF HLT:Read Mode  Is Now  3
 If HLT:Probe ID Text   Is/T1   HLT:Probe 1 ID
 Then HLT:Probe 1       T1<-T1  HLT:Probe Temp Text
 If HLT:Probe ID Text   Is/T1   HLT:Probe 2 ID
 Then HLT:Probe 2       T1<-T1  HLT:Probe Temp Text
 ENDIF
 ;
 ; Check for another byte in the buffer now, without waiting
 ; for another event pass.  This speeds up reading from the
 ; device dramatically.
 Do HLT:Byte Read  Set  HLT:Hot Little Therm
 ; Loop back to the beginning and test the HLT:Byte Read item
 ; for data.
 ENDWHILE
 End

 

So, sending the command to the device is easy, whenever you feel the need for updated
temp info, just:

 

DO HLT:Hot Little Therm SET 16

 

The event will take care of the rest.

 

Some additional things to think about:

 

The serial data may not arrive at the port in one big chunk.  Don't write an event that sets up a loop once data is received at the port and considers all of the data to be present in that loop.  A looping structure is great for processing all of the data sitting at the port, but don't count on all of it being there at once.  The above event is written to handle this.  It reads data in a looping structure as long as it's there, but doesn't make any decisions about what to do with it until it sees the appropriate terminations.  This could take one event pass,
or many.

 

I hope this helps get you started…
Brian