HP Pcl 5 Manual

ENEntity Error Codes 16-19
Entity Error Codes 
If you request out-of-range values in the command value fields, or 
if the entity is unsupported or does not exist, or if the request is 
inappropriate, the printer responds with one of four possible errors:
zInvalid Entity
zInvalid Location
zNone
zInternal Error
ERROR=INVALID ENTITY
If the entity type specified in the escape sequence is out of range 
or unsupported, an invalid entity error is returned. For example, if 
the Inquire Entity command contained...

16-20   Status ReadbackEN
ERROR=NONE
If the entity type and location are valid, but there are no entities of the 
specified type in that location, or if the type is inappropriate for the 
specified entity (internal user-defined pattern or currently selected 
macro), then an error response is generated. For example, if you 
request the downloaded symbol sets and there are no downloaded 
symbol sets, the following error response would be generated:
PCL 
INFO SYMBOLSETS 
ERROR=NONE
ERROR=INTERNAL ERROR
The...

ENFree Space Command 16-21
Free Space Command 
The Free Space command returns the amount of available memory. 
This response returns two values: the total available memory, and 
the largest available block of memory (refer to the “Memory Status 
Response” section later in this chapter for additional information).
E
C * s 1 M
If a value other than 1 is sent, this command returns an error 
(“ERROR = INVALID UNIT,” refer to “Memory Error Response” 
section later in this chapter for additional information)....

16-22   Status ReadbackEN
If you determine there is insufficient memory to hold the data to be 
downloaded, some action is required. One method to make more 
memory available is to send the Flush All Pages command. This 
causes the printer to clear (process) the current page data from 
memory without accepting any new data for processing (refer to the 
“Flush All Pages Command” described later in this section). Another, 
more comprehensive method to clear memory is to send the Printer 
Reset (
E
CE)...

ENFree Space Command 16-23 “LARGEST=” identifies the largest continuous block of available 
memory (in bytes).
An example response is shown below:
PCL 
INFO MEMORY 
TOTAL=100000 
LARGEST=25000
The above example indicates that the printer has 100,000 bytes of 
available memory and the largest continuous block is 25,000 bytes.
Memory Error Response
If the Free Memory command value field is out of range (not 1), 
then the memory status response returns an invalid unit error. For 
example, if the Free Space...

16-24   Status ReadbackEN
Flush All Pages Command 
The Flush All Pages command suspends accepting input data until all 
pages currently in the printer are printed. This gives the printer time to 
clear some memory.
E
C & r # F 
#  =0- Flush all complete pages
1 - Flush all pages
Default =0
Range =0 - 1
A value of 0 indicates that only complete pages are to be processed. 
If a partial page exists, it is not processed. A value of 1 indicates that 
all page data including the partial page will be...

ENEcho Command 16-25
Echo Command  
The Echo command echoes its value field (in ASCII format) back to 
the host.
E
C * s # X
# =Echo value (ASCII)
Default =0
Range =–32767 to 32767
If multiple users are requesting status, it can be difficult to distinguish 
one user’s status response from another. The Echo command 
provides the means to label status responses. Since the 
user-selected value for the value field is returned, this command 
can be used as a user identification mark or “place holder.”...

16-26   Status ReadbackEN
If the application sends the Echo command and Free Space 
command, the printer returns the response to the first Echo command 
and Free Space command, along with the response to the second 
request. The application will assume that the response received is the 
response to its last request. If the application uses random numbers 
in the Echo command, this type of mix-up will not occur.
Echo Response
The Echo command returns the following response:
PCL 
ECHO ValueField
where “...

ENStatus Readback Programming Hints 16-27
Status Readback Programming Hints 
The following hints can assist in using the status readback feature.
zPCL status readback is useful during the development of 
applications. Status readback allows you to determine that fonts, 
macros, user-defined patterns, and symbol set resources you 
have downloaded were accepted by the printer.
zIf the printer does not contain sufficient memory to accept a 
downloaded entity, the printer discards the data. Status readback...

16-28   Status ReadbackEN