WATLOWCLS200 Communications Specification Includes CLS200, MLS300 and CAS200

Data for a Write Command

For a block write command, the block contains the bytes to write (up to 242 bytes of data). The 

controller sends back a message packet without data.

Two-Byte Data Types

For two-byte data types, like process variable and setpoint, the controller or host software sends the data 

in two-byte pairs with the least significant byte first.

Figuring Block Size

To read parameter values, you must know how many bytes to request. Parameter values are stored 

contiguously such that the setpoints for all the loops are stored together and in loop number order. For 

example, to read the deviation alarm deadband value for loops one to five, you would read five bytes 

starting at 0x05A0. Some parameters, such as setpoint, require two bytes of memory to store. So, for 

example, if you want to read the setpoint for four loops, you must read eight bytes.

Calculate total block size in bytes for most loop parameters this way (do not forget the pulse loop):

(Data Size) * (Number of Loops)

Some parameters have values for both heat and cool. Calculate block size for such a parameter this way:

2 * (Data Size) * (Number of Loops)

One exception is the units for each loop. Calculate the data size for the units this way:

3 * (Number of Loops)

Parameters that are not loop parameters (like system status, digital inputs, or digital outputs) have 

specific data sizes. These data sizes are listed in the data table in the next section.

Anafaze/AB Data Table Summary

Each address holds one byte of data. Each parameter value requires one or two addresses to store 

depending on the type of data. The tablebelow indicates the number of bytes for each data type. The 

data type for each parameter is indicated in the tables on the following pages.

Because each loop is individually configurable, the number of instances of many parameters depends on 

the number of loops in the controller. Therefore, the number of bytes for these parameters is listed in the 

tables on the following pages in terms of the number of loops in the controller.

The storage requirements for some parameters depend on the number of digital inputs or digital outputs 

in the controller (MAX_DIGIN_BYTES and MAX_DIGOUT_BYTES). The storage of ramp-soak 

profile parameters depend on the number of profiles (MAX_RSP), the number of segments per profile 

(MAX_SEG), the number of triggers per segment (MAX_TRIG) and the number of events per segment 

(MAX_EVENT).

The table below shows the values for each of these factors. Use them to calculate the number of bytes 

for each parameter.

Ordering of Heat and Cool Channel Parameters

For parameters that have both heat and cool settings the heat values are stored in the first registers and 

the cool values are stored in the registers starting at the listed address plus MAX_CH.

Note: Data table parameters 46 to 60 and 100 are ramp-soak parameters. They are only used in 

controllers with the ramp-soak option. Parameters 81 to 95 are enhanced features and only available in 

controllers with the enhanced features option.

Ordering of Ramp-Soak Profile Parameters

Ramp-soak profile parameters are ordered first by profile, then by segment where applicable. So, for 

example, the first eight bytes of the Ready Events parameter are the ready segment event states for the 

first profile (profile A) and the next eight bytes are for profile B and so on. In the case of the segment 

triggers, the first byte contains the first trigger setting for the first segment of profile A, the second byte 

contains the settings for the second trigger for the first segment of profile A, the third byte contains the 

settings for the first trigger for the second segment of profile A and so on.