5250 error 0016: Field Minus key not valid in this field

What it means

Field- does two jobs at once. It leaves the field, as Field Exit does, and it marks the number you just typed as negative. That only makes sense in a field that can hold a signed number. IBM's DDS reference lists Field- as a valid key in signed numeric fields (shift S), numeric-only fields (shift Y) and numeric-only character fields (shift M). Press it in a text field, or any field type that doesn't take a sign, and the display station refuses it with 0016.

Many people meet 0016 because of where the key sits. In many PC emulators Field- is on the minus key of the numeric keypad. Reach for that key to type a hyphen in a name or a part number, and the emulator sends Field- instead. The text field can't take it, so the keyboard locks.

A related code, 0026, comes from the same key in a numeric-only field. There, Field- needs a digit 0 to 9 in the field's last position to carry the sign. If that position holds something else, such as a blank, a comma or a period, the display station refuses the key with 0026.

Common causes

• You pressed the minus key on the numeric keypad in a text field to type a hyphen, and your emulator maps that key to Field-.
• You tried to enter a negative value in a field that holds a number as text, such as a code or reference field with shift A.
• Your emulator's keyboard map puts Field- on a key you use for something else.
• For 0026, you pressed Field- in a numeric-only field whose last position held a blank, comma or period rather than a digit.

How to find the problem

1. Check which key you pressed. If it was the keypad minus, look at your emulator's keyboard map to see what that key sends in a 5250 session.
2. Press Help while 0016 or 0026 is on the error line to see the system's text for the error.
3. In the display file source, check position 35 for the field. Field- is valid with S, Y and M. A field with A, X or another character shift doesn't take it.

How to fix it

• Press Reset (also called Error Reset) to free the keyboard. In many PC emulators Reset is the left Ctrl key by default. Then leave the field with Field Exit or Tab instead.
• To type a hyphen in a text field, use the hyphen key on the main part of the keyboard, not the keypad.
• If you type hyphens from the keypad often, remap the keypad minus in your emulator so it sends a plain minus character. Keep Field- on another key you can reach.
• For 0026, press Reset and correct the last position so it holds a digit, or leave the field with Field+ or Field Exit.
• For programmers, if the field should take negative values, define it as numeric with shift S or Y and the right decimal positions. Recreate the display file with CRTDSPF and recompile the programs that use it if the record format level changes.

Technical reviewer: Albert Joseph, WND Software.

Last reviewed 2026-10-18 by the WND Software team. Written in our own words. For the full reference, check IBM’s 3270 or 5250 display documentation.