2. YCA Protocol
IM 249x-COMM
2
This is a protocol developed by YCA. It uses ASCII characters. All units act as
slaves in a master-slave network. There is no broadcast option.
The communications settings for the software are as follows:
Baud Rate: 9600, 4800, 2400 or 1200 bps (set using the front panel)
8 Data Bits, 1 Stop Bit, No Parity.
To communicate with the unit over a serial line the following string is sent:
<stx> <COMMAND><SP> <ADDRESS><SP> <FUNCTION><SP> <parameters> <CR> <etx>
•
The special characters ‘stx’ and ‘etx’ are standard communications codes and
most software will insert them automatically. ‘CR’ stands for ‘Carriage
Return’, also referred to as ‘Enter’. ‘SP’ stands for the ‘Space’ character.
•
The COMMAND can be one of two choices:
‘DG’
-
to get settings
‘DP’
-
to change settings
•
The ADDRESS is a two-digit number from 01 to 32. The address can only be
changed from the front panel.
Each unit in a network must have a unique number for communications to
work. The default on all units is ‘01’.
•
The FUNCTION is one of the following codes:
(Note: The functions available depend on the particular model)
Code
Function
PT
- Potential Transformer Ratio
CT
- Current Transformer Ratio
OUT1 - Analog Output for upper (
or single
) display
(upper limit, zero offset & center)
OUT2 - Analog Output for second display (
if there is one (2492/2493 only)
)
OUT3 - Analog Output for third display (
if there is one (2493 only)
)
AVG - Sample Average for all displays
LOCK - disables/Enables the keys
DISP - Show the latest measurement(s)
(works only with the ‘DG’ command.)
F
- Gives the model code
(‘DG’ only)
MIN - Show or reset minimum measurement(s) (2493 only)
MAX - Show or reset maximum measurement(s) (2493 only)
LL
- Line-to-line voltages or line-to neutral (
Voltmeters only
) (2493 only)
•
The
parameters are dependent on the function. They are not needed when
the command is ‘DG’, only for ‘DP’. See the section “
Changing Settings” for
an explanation of all the parameters.
