Manual 35086
ProTech-GII with Math Functions
Woodward
158
All values that can be addressed by the Modbus protocol are considered to be discrete or numeric. The
discrete values are a 1-bit binary 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.
Numeric values can range from –32767 to +32767 if interpreted as a signed value or from “0 to 65535” if
interpreted as an unsigned value.
Since the Modbus protocol can only handle integers, values that require a value outside of the allowable
range are multiplied by a constant, or pre-scaled, before being sent by the ProTech-GII module.
Boolean Writes (Code 05)
Because Boolean Write commands are rising edge-triggered, a write command may need to be issue first
with the discrete value set to “0” and again with the discrete value set to “1”. No password is required
when issuing a command via the Modbus interface but the module must be configured to accept Write
Commands. While selected discretes are described below, the full list available to write are listed in Table
8-3.
Initiating the Auto Simulated Speed Test
The Auto Simulated Speed Test can be started by first sending an Initiate Auto Simulated Speed Test
command, followed by a Confirm Auto Simulated Speed Test command. If the confirm command is not
sent within 10 seconds after the Initiate command is sent, the test will not be started. The intent of the
confirmation is to prevent an erroneous signal from initiating a test. The test will not start if the Abort
command is true.
Refer to the “Test Routines” Section of the “Functionality” Chapter for further test detail.
Initiate Auto Simulated Speed Test (0:0102)
This discrete provides the first command of a two-command sequence to initiate the Auto Simulated
Speed Test. This command must be followed by a Confirm command within 10 seconds or the test will
not be started. This command must be maintained true until the Confirm command is received.
Additionally the Abort command must be false or the test will not start.
Confirm Auto Simulated Speed Test (0:0101)
This discrete provides the second command of a two-command sequence to confirm initiation of the Auto
Simulated Speed Test. This command must be preceded by an Initiate command (maintained true) in the
immediately prior 10 seconds or the test will not be started.
Abort Auto Simulated Speed Test (0:0103)
This discrete provides the command to abort the Auto Simulated Speed test execution, regardless of
where it was started (Modbus or front panel). When true, prevents a Modbus commanded Auto Simulated
Speed Test from starting.
Boolean Reads (Code 02)
A Boolean Read register will have the value of “1” if the status of the monitored signal is true and a “0” if
false. While selected read discrete(s) are described below, the full list available to read are listed Table 8-
4.
Heartbeat indication (1:0284)
The Heartbeat indication provides an indication that toggles every one second between logic 1 and logic
0.
Analog Reads (Code 04)
Analog values are transmitted as 16-bit integer values ranging from –32767 to +32767 (if signed) or 0 to
65535 (if unsigned). For values that can exceed the 16-bit range, the value may also be multiplied by a
constant before it is transmitted. When the value is pre-scaled in this manner, the parameter description
will include an indication to this effect. Some values, like the Timer values, are sent using more than one
register. While selected analogs are described below, the full list available to read are listed in Table 8-5.
Scaled Speed and Acceleration Values (3:0001 to 3:0012)
Scaled values of the sensed speed, calculated acceleration and RM-selected speed and acceleration are
provided as analog signals.
Released