ProTechTPS Total Protection System
Manual 26710V1
88
Woodward
Modbus Communication Port Settings
Parameter
Range
Mode:
RS-232 or RS-485
Baud Rate:
19200 TO 115200
Comm Parity:
NONE, ODD or EVEN
Slave Address:
1 - 247
Enable Write Commands:
Yes or No
Table 4-3. Modbus Serial Communication Port Settings
ProTechTPS Parameter Addresses
Each available read or write parameter has a unique Modbus address. A
complete list of the available parameters and their addresses is located at the
end of this chapter. This list consists of Boolean Write, Boolean Read, and
Analog Read parameters. Analog write parameters are not used or available with
this device. Reserved address ranges can be read, but they are undefined for
ProTechTPS.
All values that can be addressed by Modbus are considered to be discrete and
numeric. The discrete values are a 1 bit binary on or off value, and the numeric
values are 16 bit values. Discrete values are sometimes referred to as coils or
digitals, and numeric values are referred to as registers or analogs. All read/write
registers are interpreted by the ProTechTPS as signed 16 bit integer values.
Since Modbus can only handle integers, values that require a decimal point in the
Modbus Master Device are multiplied by a scaling constant before being sent by
ProTechTPS. See the Modbus list for the scaling used on each analog
parameter.
Boolean Writes (Code 05)
Boolean Write registers are used by an external master device (plant DCS, etc.)
to issue Boolean commands to a ProTechTPS module. No password is required
when issuing a command using Modbus. The available write commands are
listed in Table 4-3.
Once a Modbus port’s “Enable Write Commands” setting is configured “Yes”, the
respective ProTechTPS module will accept “write” commands from an external
master device (DCS, etc.).
NOTE—All write commands are edge-triggered.
Initiating a test mode
Only one test mode can be active at a time. Depending on the “Test Mode
Permissive” setting, attempts to start a test may be ignored when another test
mode is active, another module is tripped, another module is in a test mode, or
another module is in alarm.
Speed/user tests must be requested by first setting the Initiate bit, followed by
setting the confirm bit. If the Confirm bit is not set within 10 seconds after the
initiate bit is set, then the test will not be requested.
Note that the confirm-initiate addresses are in reverse order so that an initiate
followed by a confirm cannot be executed by a single write command. Both bits
must be set to 0 before starting the initiate-confirm sequence.
If an Abort command is set to 1, an initiate-confirm sequence shall be ignored.
