Rice Lake Dual Ramp Wheelchair Platform Scale with Seat (350-10-4) - Rice Lake - Manual (Page 23)

Wheelchair Scale with Seat Technical Manual - RS-232 Communication 19
7.2 Communication Protocols
The Rice Lake Digital Wheelchair Scale with seat has two communication protocols, escape and maintenance protocol.
7.2.1 Escape Protocol
An escape protocol is where the escape (0X1B or ASCII 27) is used to indicate that there is a command
following. On the PC side there must be a listener created by the vendor that will interpret this protocol. This
listener must also take care of all the issues regarding data integrity, etc. to make sure that the data that was sent
and received is valid.
Two examples include:
• Scale initiated communication
• PC initiated communication
Table 7-1 is what can be sent across communications lines.
Table 7-1. Escape Protocol Commands
PC Initiated ESC Value
Request current values/settings R
Diagnostics A
Send scale control messages C
PC Initiated ESC Value
Send single reading R
Send diagnostic response
Table 7-2 lists the ESC characters that will be used.
Table 7-2. ESC Characters
Name ESC character
ESC value with
parameters Description
Reading R R Tells the PC that the scale is sending a reading. Immediately following
this is the value that is sent. Example:
<ESC><R>ESC><W0200.0<ESC>Nm<ESC>E
Weight W Wnnn.n Is the patient weight (example: W02000 means 200.0). If the scale is
overloaded or under loaded, the scale will return the value 999.99.
Height H Hnnn.n Patient height
BMI B Bnn.n Patient BMI
Units N Nc Indicates in which unit the values have been taken (m=metric,
c=constitutional).
End of Packet
(EOP) E E Indicates that the end of the command has been reached.
Diagnostics
(request) A Accc A request for a diagnostic test on certain parts of the scale (such as
battery life, load cells).
Diagnostics
(response) Z Zccc This will be the response of the diagnostics done on the scale. Values
will include error codes to indicate what is wrong with the scale, or all
zeros (Z000) to indicate that all is well.
Control (set a
value) C Cccc=c Sets the value of the scale’s global settings. Example:
<ESC><CUOM=m><ESC><E will set the unit of measurement.
Table 7-3. Scale Global Values List and Identifiers
Name of Control Identifier Unit
Unit of Measure (metric or constitutional) UOM c (m or c)